A tennis racket principally consists of a head or frame element for supporting a set of strings that are interlaced in a spaced apart woven pattern, a throat and a handle element. When the racket is initially strung the tension of the strings is carefully controlled in accordance with the preference of the player for whom the racket is being strung. Normally the main and cross strings are stretched to a tension of a 60 or 70 pounds pull but some players prefer a lighter tension as low as even a 40 pounds pull. No matter how low or how high the tension is controlled in the stringing process, during play it has frequently been observed that the crossing pattern of the woven strings is disturbed. When this happens, a particular string or more usually several strings near the center of the frame area, principally the crossing strings are bowed away from their usual 90.degree. crossing pattern.
When a string is stretched to a bowed position away from its original position it is elongated and obviously the original tension of the string system in the racket has been changed. This modifies the hitting properties of the racket and consciously or unconsciously affects the player's control of the ball as it leaves the surface of the racket and has a bearing on the direction and velocity of the ball in its path of travel.
Therefore, it is desirable to control the position of the individual strings in the woven pattern as closely as possible to their original positions at all times in order to maintain the designed tension in the hitting area in the bow or frame of the racket. Heretofore it has been the practice of tennis players to use the tips of their fingers to pull the strings back to their approximately correct positions from time to time when they have completed their active playing session.
______________________________________ Prior Art U.S. Pat. Nos.; ______________________________________ 1,514,273 to Van Schenk Nov. 4, 1924 2,156,092 to Johnson Apr. 25, 1939 4,082,272 to Garver Apr. 4, 1978 4,089,523 to Newburger et al May 16, 1978 4,359,213 to Bachman et al Nov. 16, 1982 4,489,942 to Kent Dec. 25, 1984 4,733,866 to Herbert Mar. 29, 1988 4,776,591 to Ho Oct. 11, 1989 3,135,521 to Langenbach (W. Germany) Mar. 24, 1883 ______________________________________
The above listed patents were made of record in my prior application to show various devices that have a bearing on the art of manipulating the strings in the head element of a tennis racket to maintain the strings in their designed positions during the stringing operation or to return them to a proper position in their respective woven patterns.
The U.S. Pat. Nos. 2,156,092 to Johnson, Apr. 25, 1939; 4,082,272 to Garver Apr. 4, 1978 and 4,359,213 to Bachman Nov. 16, 1982 all show devices that are useful during the initial stringing operation for mounting the woven pattern of strings in the head or frame of the racket. These disclosures all relate to the original setting of the strings and are not concerned with nor are they useful for resetting the strings after play with the racket has been completed, and during which play action the reaction of the ball against the strings may have caused some unwanted displacement of the strings from their normal pattern.
The U.S. Pat. Nos. 4,089,523 to Newburger et al; 4,489,942 to Kent; and the German patent show one form of a string straightener device that can be used on bowed strings in a tennis racket that has been in use and 4,733,866 to Herbert and 4,776,591 to Ho show other forms of such a means.
The U.S. Pat. Nos. to Johnson 2,156,092, to Garver 4,082,272 and Bachnan 4,359.213 all show means used during the initial stringing operation for producing the original woven pattern in the head of a racket.
With respect to the two groups of patents mentioned above, the patents used during the initial stringing of a racket are of interest in connection with this invention, only in the broadest sense of the stringing art in showing how strings may be confined initially to a parallel or other position. There is no suggestion in either of these disclosures for using the means shown therein for straightening the strings in a racket head that has been used.
The first listed group of patents includes two patents, Newberger et al and Kent that both show rather unwieldy plate means having fixed teeth with a pyramidal shape adapted to move strings back into their original positions when pressed into the openings in the woven Pattern. These types of devices may be adequate, assuming that the spaces between the strings and the fixed teeth and their shapes are all of a standard pattern, but many of the tennis rackets in use today are strung with different woven patterns using differently spaced strings and there seems to be no standard sized shapes or sizes of spacings between the main and cross strings in many of the modern rackets.
The German patent like Newburger and Kent is adapted for use on rackets having a standard spacing between its strings. This patent depicts a device having fixed teeth, spaced apart to engage the strings of a racket to move them back into position when they have been displaced during play.
Herbert and Ho show string straightening means for use on different tennis rackets that may have strings spaced apart in different patterns. In each of these respective patents adjustably mounted string engaging pegs or teeth means are described, that must be adjusted to fit the particular string arrangement of each racket upon which the respective devices are to be used. After the pegs or teeth have been individually moved to a proper setting, they are locked in place for cooperating with the strings. This procedure requires a great deal of patience and especially when the device must be adjusted several times as the string staightener is moved across the entire face of the racket, as may be necessary when straightening the strings across the entire face of a racket, many of which have heads with shapes such that one setting of the pegs or teeth in either of their respective racks will not fit all the strung areas within the frame that must be attended to.
Another of the patents listed above is the patent to Van Schenk who shows an upholstering tool that has a series of fixed teeth for engaging and then stretching webbing in a chair structure or the like which would appear to have little relevance to the subject matter of this invention.
It is the purpose of this invention to provide a means for easily and quite accurately moving the individual bowed strings back to each of their assigned positions to which they were originally set when strung in the head, in order to maintain the proper string interaction that is produced by pulling the designed tension in each string during the original stringing operation.
It is another purpose of this invention to provide a string straightener device that can be automatically fitted to any particular pattern of woven strings as the device is being placed in position on the surface of the string pattern.
It is another purpose of this invention to make a device available that can be temporarily and easily placed on the strings in the frame adjacent a bowed string whatever the string pattern and then be manually operated to quickly return the bowed string to its original setting in the woven pattern.
It is yet another purpose of this invention to provide a device that coacts with the individual strings in various woven patterns to assuredly guide a bowed string back to its original setting in its respective pattern to preserve the original tension of the string in that woven pattern whereby to maintain the designed feel in the racket when striking a ball.
It is another purpose of this invention to make a device available that is easily portable and that can be quickly attached to the racket adjacent a bowed string and manually operated to return the string to its correct setting in order to preserve the proper tension in that string.
Other objects of the invention will appear more fully from the description below.